1. Field of the Invention
This invention relates to novel bisphosphoryl derivatives of hydrazine, and to compositions thereof which are useful in controlling agricultural pests such as insects, especially the corn rootworm.
Of the insects and other pests which attack the corn plant, the corn rootworm is particularly difficult to control. Corn rootworms are the larvae of beetles of the genus Diabrotica which cause damage to corn plants, especially in fields where one corn crop follows another in successive seasons. The adult beetles lay eggs in the soil of a maturing crop where the eggs lie dormant until Spring; the hatching larvae feed on the roots of young corn plants reducing yield or causing the plants to topple over under influence of climatic conditions. The fallen stalks cannot be harvested by mechanical means, and significant loss of yield results. Control of soil insects such as the corn rootworm is difficult because most pesticides are quickly inactivated by soil bacteria and fail to control the insect population throughout the growing season.
We have found that bisphosphoryl hydrazine compounds are active in the soil for a sufficient period of time to control the corn rootworm as well as other insect pests such as turf grubs and have low toxicity to mammals.
2. Description of the Prior Art
Tolkmith (U.S. Pat. No. 2,968,688) describes compounds of the general formula: ##STR1## wherein R and R' are radicals containing up to four carbon atoms which are lower alkoxy, mono-lower alkylamino radicals or di-lower alkylamino radicals wherein each of the alkyl groups up to four carbon atoms. Rand R' may be the same or different radicals. These compounds are active as herbicides and systemic insecticides, especially for the mexican bean beetle.
Tolkmith (U.S. Pat. No. 2,945,055) reports a general compound structure of the type: ##STR2## wherein R and R' have the same definition as in U.S. Pat. No. 2,968,688. The '055 structures are unsymmetrical while the '688 compounds are symmetrical. These compounds are reported to be fungicides and insecticides against the southern armyworm. There is no reported activity against the corn rootworm.
Englin, et al., CA 69 p. 4882,52212(1968) describe the preparation of compounds represented by the following structure: ##STR3## wherein R is isobutyl. These products were prepared for evaluation as biocides.